Stephen Berman <stephen.berman@gmx.net> writes:

> I also tried and failed to get Edebug to kick in here, but I did make an
> observation that surprised me but I assume is somehow relevant: if I
> start Emacs with -Q, insert your sample perl code in a new buffer,
> invoke cperl-mode, go to line 44 and type C-k, Emacs hangs, as you
> discovered -- but if, after starting with -Q and inserting the sample
> code I first invoke perl-mode and after the buffer fontifies invoke
> cperl-mode, now when I go to line 44, C-k kills the line as it should
> and there is no other problem, even if I then change the buffer to some
> other mode and then back to cperl-mode again.

Since there seems to be inconsistend behavior, would you mind trying my
patch and making sure none of the scenarios you've tried so far causes
Emacs to hang?